An Efficient R-Estimator for the ED50

Abstract

Analogues of R-estimators are defined for the problem of estimating the median of a symmetric tolerance distribution in quantal bioassay. Asymptotic distributions are derived, and it is shown that the logistic scores estimator is, in a certain sense, asymptotically efficient. A Monte Carlo study is conducted to investigate the small-sample behavior of this estimator in relation to 10 competing estimators. The results suggest that the logistic scores estimator merits further consideration.

Key Words:

• Quantal bioassay
• Median effective dose
• Spearman-Kärber
• Trimmed Spearman-Kärber
• Logistic scores estimator
• Asymptotic efficiency